Les Défis de la Comté Marcel Petite is a Friday-evening trail running series in the Haut-Doubs, with each start set for 19:30 after the workday. The format includes four separate runs of about 10 km, all on natural terrain, with Malbuisson serving as the fourth stage.
The series moves through Levier, Pontarlier, Sombacour, and Malbuisson, giving it the feel of a local tour rather than a single race day. Runners can go at their own pace, suiting club runners, casual runners, and those seeking a relaxed challenge. The atmosphere is friendly and festive, with the social aspect as important as performance.